refoactor call site some

lib/typed/ast/call_site.rb

@@ -1,5 +1,7 @@
 module Typed
-  class CallSite < Expression
-    attr_accessor :name , :receiver , :arguments
+  module Tree
+    class CallSite < Expression
+      attr_accessor :name , :receiver , :arguments
+    end
   end
 end

lib/typed/ast/to_code.rb

@@ -117,7 +117,7 @@ module Typed
 
     def on_call statement
       name_s , arguments , receiver = *statement
-      w = CallSite.new()
+      w = Tree::CallSite.new()
       w.name = name_s.children.first
       w.arguments = process_all(arguments)
       w.receiver = process(receiver)